1. Field of the Invention
The present invention is generally related to a cover structure that is specifically shaped to comprise air conduits and, more particularly, to a flywheel cover for an outboard motor which has fluid passages formed therein for the purpose of conducting air between an inlet opening and an outlet opening.
2. Description of the Prior Art
It is well known to those skilled in the art that certain components of an outboard motor, such as a flywheel and other moving parts, should be covered in order to protect the operator when the cowl is removed. In certain applications of outboard motors, the flywheel cover is provided with an opening in its surface through which air can flow. Typically, an air filter is placed within a chamber at the inlet opening and a hose is connected in fluid communication with the chamber to direct a flow of air towards the inlet of a compressor. In other applications, the hose which is connected to the air compressor is not connected to the flywheel cover, but, instead, is independently supported by other means.
Another flow of air is directed from a region around the outside surface of the internal combustion engine toward the air inlet of the engine. This flow of air also passes along a path under the flywheel cover. In certain applications, individual sound dampening structures are used to reduce the noise caused by the air flow.
U.S. Pat. No. 5,133,307, which issued to Kurihra on Jul. 28, 1992, discloses an air intake system for a marine propulsion engine. The air intake system is provided with an U-shape configuration for facilitating water separation and to provide a long intake passage. An air flow sensor is positioned at the inlet opening of the inlet device with the lift being the inlet opening and the intake port being effective to dampen pulsations in the induction systems from the air flow device.
U.S. Pat. No. 5,501,202, which issued to Watanabe on Mar. 26, 1996, describes an engine component layout for an outboard motor. The engine of an outboard motor includes an improved engine component layout in order to minimize the size of the engine and to improve the performance of the components. A separator of a crankcase ventilation system is located on a cam cover outside the cam chamber in order to reduce the size of the cam cover while providing the necessary spacing between the separator and the valve mechanism within the cam chamber. A fuel pump is positioned at about the center of the cam cover, beneath the separator, in order to generally balance the length of fuel travel to each of the carburetors. A fuel filter is located on the cam cover and positioned to generally isolate the fuel filter from the effects of the heated cylinder head and block. The arrangement of these components does not interfere with the hingelike travel of the top cowling, which surrounds the engine, relative to a lower tray.
U.S. Pat. No. 4,760,704, which issued to Torigai on Aug. 2, 1988, describes a multi-cylinder engine with a turbo charger. A number of embodiments of a two-cycle, turbo-charged internal combustion engine are described in this patent for providing an improved arrangement for locating the inlet of the turbine stage so as to minimize the necessity for back flow in the exhaust conduit. A number of embodiments are also illustrated for applying this principal to outboard motors and in many of the embodiments, twin turbo-charges are employed. The turbo-chargers are disposed in such a relationship so as to permit a compact relationship and to avoid close proximity between the exhaust conduits and the compressor stages.
U.S. Pat. No. 5,488,939, which issued to Nakai et al on Feb. 6, 1996, discloses a crankcase ventilation system for an outboard motor. The ventilation system is provided for an engine crankcase of a marine outboard motor in order to distribute blow-by gas generally equally to each cylinder while minimizing the size of an intake silencer of the system. The intake silencer includes a first expansion chamber into which the blow-by gas is introduced from a blow-by gas chamber attached to the cylinder head. The blow-by gas diffuses and mixes with ambient air which is drawn into the first expansion chamber through an inlet port of the induction system. The air/blow-by gas mixture is then drawn into a second expansion chamber where it distributes generally evenly before induction into a charged forming device.
Because of the need of arranging components of an outboard motor efficiently while also performing the necessary functions, which include directing air to an air compressor and to the air inlet of the internal combustion engine, it would be beneficial if a means could be provided for combining the functions of two or more components of the outboard motor. For example, it would be particularly beneficial if a flywheel cover could be constructed in a way that eliminates the need for separate hoses to direct air flow to the air compressor and to the air inlet of the internal combustion engine while also serving as a locator to properly position the flywheel cover on the engine. If these functions could be performed by the flywheel cover, in addition to the normal function of providing protection for an operator when the cowl is removed, a significant improvement in the structure of an outboard motor could be achieved.